The present invention is directed to an alarm system that protects a premises, and which communicates with a central, remote reporting station, through the local telephone line of the PSTN connected to the premises-wiring of the protected premise. Typical, conventional alarm systems are installed in such a manner as to allow the alarm control-panel the capability of seizure of the PSTN line for transmitting the alarm-condition alarm signals to its central office, or central station, without hindrance. This has been achieved by routing the incoming PSTN line through the alarm control (C/C) panel itself. The current implementation requires the installer to locate the incoming line. The installer then must modify the line to run through the alarm C/C panel before feeding into the house telephone-wiring using an RJ-31X interconnect. When the alarm C/C panel must communicate an alarm-condition message to the central office, it seizes the PSTN line, which also causes the house telephone line to be disconnected from the PSTN line,xe2x80x94and, therefore, any telephone device connected thereto. The alarm control pane then dials into its message center at the central station, and downloads its alarm-message information. During this time, the house or premises telephones are not operational.
There are also known alarm systems that monitor a premises for an alarm-condition and report such alarm-condition to a central station using either the PSTN as the primary link and a radio link as the secondary backup. Examples of these are shown in U.S. Pat. No. 4,718,079xe2x80x94Rabito, U.S. Pat. No. 5,131,019xe2x80x94Sheffer, et al., and U.S. Pat. No. 4,887,290xe2x80x94Dop, et al There are also prior-art systems that use the radio link as the primary link, and the PSTN line as the secondary, or backup, link. Examples of these prior-art system are shown in U.S. Pat. No. 5,146,486 xe2x80x94Lebowitz, and U.S. Pat. No. 5,454,024xe2x80x94Lebowitz. In either type of system, a fault detector or monitor detects the outage or fault of the primary link and automatically switches over the connection of the alarm-panel to the secondary link. In the first type of system, a line-fault detector detects outage of the PSTN line-connection, while in the second type of system, the fault detector is a RF-fault detector.
The present invention is directed to the allowing of the house or premises telephones to have access to the PSTN network during the time an alarm C/C panel is attempting, or in the process of, communicating its alarm-messaging to the central office, and not only switches over to a backup radio link upon the detection of the outage of the PSTN line, but also switches over to the radio backup link when a telephone device connected to the premises wiring is, or is about to, make a call. The present invention also reduces cost, complexity, and time of the installation process of an alarm system which communicates a message to a central station, or other remote location
It is, therefore, the primary objective of the present invention to provide an alarm-monitoring and reporting system for a house or other premises that automatically switches over its reporting functions to a cellular-based, cellular-like, or the radio, telephone network if the PSTN line is being utilized by a house or premises telephone device, such as a POTS telephone, fax, modem, or other telephone-like device.
It is, also, the primary objective of the present invention to provide such an alarm-monitoring and reporting system for a house or other premises that automatically switches over its reporting functions to a cellular-based, cellular-like, or the radio, telephone network if the PSTN line is being utilized by a house or premises telephone device, that requires a simple installation alarm system which will also allow the system to transmit alarms over the PSTN telephone network when such is not in use by a telephone device.
Accordingly, the alarm system of the invention includes a alarm-panel interface device that monitors the line-condition of the premises-wiring of the protected premises in order to determine if the line is in use. If the premises-wiring line is not in use, the system allows the alarm panel to call into the central office over the PSTN network. If the line is being utilized, the device will redirect the call over a backup radio link, such as the cellular, or cellular-like network. The system also monitors the success of its communication to the central station. If the communication of the messaging to the central station fails for some reason, as, for example, it has been interfered with by another device on the line, then the alarm C/C panel will hang up and attempt a retransmission of the message. The system detects this failure, or, alternatively, a specified number of failed attempts, and disconnects the alarm panel from the PSTN telephone line. Subsequent re-transmissions of the communication are then directed through a backup radio link, such as the switched cellular network.